NASA/Lockheed Martin X-59A Quiet Supersonic Technology (QueSST)

The flight campaign is due to resume in March, starting with 10 “envelope expansion” flights, a spokesperson at NASA Langley told me by email. Test pilots will gradually fly the aircraft “higher and faster, reaching the mission test point of 55,000ft and Mach 1.5.”

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Two retired U.S. Air Force F-15 jets have joined the flight research fleet at NASA’s Armstrong Flight Research Center in Edwards, California, transitioning from military service to a new role enabling breakthrough advancements in aerospace.

The F-15s will support supersonic flight research for NASA’s Flight Demonstrations and Capabilities project, including testing for the Quesst mission’s X-59 quiet supersonic research aircraft. One of the aircraft will return to the air as an active NASA research aircraft. The second will be used for parts to support long-term fleet sustainment.

“These two aircraft will enable successful data collection and chase plane capabilities for the X-59 through the life of the Low Boom Flight Demonstrator project” said Troy Asher, director for flight operations at NASA Armstrong. “They will also enable us to resume operations with various external partners, including the Department of War and commercial aviation companies.”

The aircraft came from the Oregon Air National Guard’s 173rd Fighter Wing at Kingsley Field. After completing their final flights with the Air Force, the two aircraft arrived at NASA Armstrong Dec. 22, 2025.

“NASA has been flying F-15s since some of the earliest models came out in the early 1970s,” Asher said. “Dozens of scientific experiments have been flown over the decades on NASA’s F-15s and have made a significant contribution to aeronautics and high-speed flight research.”

The F-15s allow NASA to operate in high-speed, high-altitude flight-testing environments. The aircraft can carry experimental hardware externally – under its wings or slung under the center – and can be modified to support flight research.

Now that these aircraft have joined NASA’s fleet, the team at Armstrong can modify their software, systems, and flight controls to suit mission needs. The F-15’s ground clearance allows researchers to install instruments and experiments that would not fit beneath many other aircraft.

NASA has already been operating two F-15s modified so their pilots can operate safely at up to 60,000 feet, the top of the flight envelop for the X-59, which will cruise at 55,000 feet. The new F-15 that will fly for NASA will receive the same modification, allowing for operations at altitudes most standard aircraft cannot reach. The combination of capability, capacity, and adaptability makes the F-15s uniquely suited for flight research at NASA Armstrong.

“The priority is for them to successfully support the X-59 through completion of that mission,” Asher said. “And over the longer term, these aircraft will help position NASA to continue supporting advanced aeronautics research and partnerships.”

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NASA Adds Two F-15 Aircraft to Support Supersonic Flight Research - NASA

Two retired U.S. Air Force F-15 jets have joined the flight research fleet at NASA’s Armstrong Flight Research Center in Edwards, California, transitioning

www.nasa.gov

Jan 30, 2026
NASA’s Armstrong Flight Research Center in Edwards, California, has been at the forefront of aviation innovation for decades – from historic X-planes to today’s cutting-edge research shaping the future of flight. In this exclusive conversation, NASA Administrator Jared Isaacman joins test pilots Nils Larson and Jim “Clue” Less to discuss Armstrong’s legacy, the role of X-planes in advancing technology, and what the next era of aeronautics might look like.

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Kiltonge said:

Incredible, 10 'envelope expansion' flights required to get to Mach 1.4, before it even starts to do any science.

The N-156 went supersonic on its first flight, 67 years ago.

What's gone wrong? We have all the tools to predict how this thing will fly. Is it simply an overabundance of risk aversion? Self-preserving project management? Lack of impetus? Exploitation of budget?

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Arjen said:

Has anybody considered that X-59A might be about producing a.reasonably accurate computer model, validated by hardware?

Just asking.

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Kiltonge said:

Its possible, but seems like a self-licking lollipop.

The purpose of the X-59 is to demonstrate that low-boom sonic flight is tolerable. The design isn't generally applicable to future aircraft, due to impracticality, so any computer model would likewise lack forward applicability.

Essentially it would be validating itself for the sake of validation. Which, IMHO, sums up the X-59.

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The aircraft took off at 10:54 a.m. PDT from Edwards Air Force Base, near NASA Armstrong. Several minutes into the flight, pilot Jim “Clue” Less saw a vehicle system warning in the aircraft’s cockpit. Following flight procedures, the aircraft landed at 11:03 a.m. after a return-to-base was called.

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X-59 second flight abbreviated due to technical issue

Lockheed Martin X-59 quiet supersonic technology (QueSST) X-plane second flight abbreviated due to technical issue

theaviationgeekclub.com

NASA Administrator Jared Isaacman

And we are planning to fly X-59 again tomorrow. We are getting back into a flight test groove. Like most things at NASA, we want to execute safely, with urgency, and achieve the objectives. Because whatever comes next should be that much more impressive, ambitious, and inspiring

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NASA’s X-59 Returns To Flight After False Positive Cockpit Warning​

NASA’s X-59 Returns To Flight After False Positive Cockpit Warning | Aviation Week Network

The cockpit warning light that cut short the second flight of NASA’s X-59 low-boom supersonic flight demonstrator on March 20 proved to be a false positive.

aviationweek.com

Podcast: Can NASA’s X-59 And Boom’s Overture Really Deliver A New Era Of Supersonic Travel?​

Podcast: Can NASA’s X-59 And Boom’s Overture Really Deliver A New Era Of Supersonic Travel? | Aviation Week Network

As NASA begins X-59 envelope expansion and Boom develops its first high speed engine, civil supersonic activity is at its highest since the retirement of Concorde in 2003. Editors discuss the latest developments and the challenges that lie ahead.

aviationweek.com

In a pair of test flights on April 10 and April 14, the aircraft reached new altitudes and speeds, reaching 43,000 feet and 528 to 627 mph (approximately Mach 0.8 to 0.95 in those conditions). Those flights were the eighth and ninth overall for the X-59 and marked a jump from its previously reached altitude of 32,000 feet, attained on April 7.

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Latest NASA X-59 Flights Go Higher and Faster - NASA

NASA’s X-59 experimental aircraft has made its highest and fastest flights so far, expanding its operational range and making progress toward supersonic flight.

www.nasa.gov